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Annotated edit history of errno(3) version 1, including all changes. View license author blame.
Rev Author # Line
1 perry 1 ERRNO
2 !!!ERRNO
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 SEE ALSO
7 ----
8 !!NAME
9
10
11 errno - number of last error
12 !!SYNOPSIS
13
14
15 #include
16
17
18 extern int errno;
19 !!DESCRIPTION
20
21
22 The integer __errno__ is set by system calls (and some
23 library functions) to indicate what went wrong. Its value is
24 significant only when the call returned an error (usually
25 -1), and a library function that does succeed is allowed to
26 change __errno__.
27
28
29 Sometimes, when -1 is also a legal return value one has to
30 zero __errno__ before the call in order to detect
31 possible errors.
32
33
34 __errno__ is defined by the ISO C standard to be a
35 modifiable lvalue of type __int__, and must not be
36 explicitly declared; __errno__ may be a macro.
37 __errno__ is thread-local; setting it in one thread does
38 not affect its value in any other thread.
39
40
41 Valid error numbers are all non-zero; __errno__ is never
42 set to zero by any library function. All the error names
43 specified by POSIX.1 must have distinct values.
44
45
46 POSIX.1 (1996 edition) lists the following symbolic error
47 names. Of these, __EDOM__ and __ERANGE__ are in the
48 ISO C standard. ISO C Amendment 1 defines the additional
49 error number __EILSEQ__ for coding errors in multibyte or
50 wide characters.
51
52
53 __E2BIG__
54
55
56 Arg list too long
57
58
59 __EACCES__
60
61
62 Permission denied
63
64
65 __EAGAIN__
66
67
68 Resource temporarily unavailable
69
70
71 __EBADF__
72
73
74 Bad file descriptor
75
76
77 __EBADMSG__
78
79
80 Bad message
81
82
83 __EBUSY__
84
85
86 Resource busy
87
88
89 __ECANCELED__
90
91
92 Operation canceled
93
94
95 __ECHILD__
96
97
98 No child processes
99
100
101 __EDEADLK__
102
103
104 Resource deadlock avoided
105
106
107 __EDOM__
108
109
110 Domain error
111
112
113 __EEXIST__
114
115
116 File exists
117
118
119 __EFAULT__
120
121
122 Bad address
123
124
125 __EFBIG__
126
127
128 File too large
129
130
131 __EINPROGRESS__
132
133
134 Operation in progress
135
136
137 __EINTR__
138
139
140 Interrupted function call
141
142
143 __EINVAL__
144
145
146 Invalid argument
147
148
149 __EIO__
150
151
152 Input/output error
153
154
155 __EISDIR__
156
157
158 Is a directory
159
160
161 __EMFILE__
162
163
164 Too many open files
165
166
167 __EMLINK__
168
169
170 Too many links
171
172
173 __EMSGSIZE__
174
175
176 Inappropriate message buffer length
177
178
179 __ENAMETOOLONG__
180
181
182 Filename too long
183
184
185 __ENFILE__
186
187
188 Too many open files in system
189
190
191 __ENODEV__
192
193
194 No such device
195
196
197 __ENOENT__
198
199
200 No such file or directory
201
202
203 __ENOEXEC__
204
205
206 Exec format error
207
208
209 __ENOLCK__
210
211
212 No locks available
213
214
215 __ENOMEM__
216
217
218 Not enough space
219
220
221 __ENOSPC__
222
223
224 No space left on device
225
226
227 __ENOSYS__
228
229
230 Function not implemented
231
232
233 __ENOTDIR__
234
235
236 Not a directory
237
238
239 __ENOTEMPTY__
240
241
242 Directory not empty
243
244
245 __ENOTSUP__
246
247
248 Not supported
249
250
251 __ENOTTY__
252
253
254 Inappropriate I/O control operation
255
256
257 __ENXIO__
258
259
260 No such device or address
261
262
263 __EPERM__
264
265
266 Operation not permitted
267
268
269 __EPIPE__
270
271
272 Broken pipe
273
274
275 __ERANGE__
276
277
278 Result too large
279
280
281 __EROFS__
282
283
284 Read-only file system
285
286
287 __ESPIPE__
288
289
290 Invalid seek
291
292
293 __ESRCH__
294
295
296 No such process
297
298
299 __ETIMEDOUT__
300
301
302 Operation timed out
303
304
305 __EXDEV__
306
307
308 Improper link
309
310
311 Many other error numbers are returned by various Unix
312 implementations. System V returns ETXTBSY (Text file busy)
313 if one tries to exec() a file that is currently open for
314 writing. Linux also returns this error if one tries to have
315 a file both memory mapped with VM_DENYWRITE and open for
316 writing.
317 !!SEE ALSO
318
319
320 perror(3), strerror(3)
321 ----
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